Method and apparatus for image encoding/decoding

Abstract

Disclosed are a method and an apparatus for image encoding / decoding. The method for image decoding includes comparing whether a size of a current transform block and a size of a smallest transform block (smallest transform unit (STU)) are the same as each other, and decoding information indicating whether transformation is performed on the current transform block and determining whether to perform inverse transformation on the current transform block based on the decoded information indicating whether the transformation is performed when the size of the current transform block and the size of a smallest transform block are the same as each other.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of priority of Korean Patent Application No. 10-2013-0022145 filed on Feb. 28, 2013, and Korean Patent Application No. 10-2013-0024978 filed on Mar. 8, 2013, all of which are incorporated by reference in its entirety herein.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to image encoding / decoding, and more particularly, to a method and an apparatus for encoding / decoding an image by determining whether to transform the image.[0004]2. Related Art[0005]In recent years, a demand for high-resolution and high-quality images such as a high definition (HD) image and an ultra high definition (UHD) image has increased in various application fields. As image data has high resolution and high quality, data quantities are relatively increased as compared with the existing image data, and as a result, when image is transmitted by using a medium such as the existing wired...

AI Technical Summary

Benefits of technology

[0007]An object of the present invention is to provide a method and an apparatus for image encoding / decoding that can improve encoding / decoding efficiency.

[0008]Another object of the present invention is to provide a method and an apparatus that determine whether to transform an image based on a size of a smallest transformation block capable encoding / decoding efficiency.

[0024]Whether to transform a current transformation block is determined based on a size of the smallest transformation block and the determined information is efficiently signaled to increase encoding efficiency and improve a subjective image quality.

[0025]If degree of spatial change of pixel values in a corresponding block to be compressed in the image is very large or very sharp, and as a result, degree in which image energy concentrates on low frequencies in spite of transformation is not significant and when serious image quality deterioration is caused by primarily maintaining low-frequency components and removing high-frequency components or strongly applying quantization during a compression process, whether to perform transformation may be determined based on the size of the smallest transformation block without large overhead by judgment of an encoder to increase image compression rate and minimize image quality deterioration.

Problems solved by technology

As image data has high resolution and high quality, data quantities are relatively increased as compared with the existing image data, and as a result, when image is transmitted by using a medium such as the existing wired / wireless wideband line or the image data is stored by using the existing storage medium, transmission cost and storage cost are increased.

Images